JP2023525029A - Actively controlled power transformer and its control method - Google Patents

Abstract

A transformer (100, 200, 300, 500) includes a magnetic core (102) having multiple limbs (104-106). The transformer also includes a direct current (DC) bias winding (110) wrapped around one predetermined limb. The transformer further includes a DC amplifier (112) electrically connected to the DC bias winding. A DC amplifier is configured to receive a first signal (114) related to the load output current or voltage. The DC amplifier is also configured to determine the amount of current in the DC bias winding based on the first signal. The DC amplifier is further configured to send the determined amount of current through the DC bias winding.

Description

The present disclosure is directed generally to power systems. More specifically, the present disclosure is directed to actively controlled power transformers and methods of controlling the power transformers.

Many existing power systems, such as those used in radar systems, use heavy external electrical equipment to limit current inrush and harmonic filtering to the main power transformer. Unfortunately, conventional passive filters typically overcompensate for input line power, which can cause system voltage levels to exceed normal levels when the power system is lightly loaded.

The present disclosure relates to actively controlled power transformers and methods of controlling power transformers.

In a first embodiment, a transformer (100, 200, 300, 500) includes a magnetic core (102) having multiple limbs (104-106). The transformer also includes a direct current (DC) bias winding (110) wrapped around one predetermined limb. The transformer further includes a DC amplifier (112) electrically connected to the DC bias winding. A DC amplifier is configured to receive a first signal (114) related to the load output current or voltage. The DC amplifier is also configured to determine the amount of current in the DC bias winding based on the first signal (114). The DC amplifier is further configured to send the determined amount of current through the DC bias winding. and a magnetic flux sensor (204) positioned within a gap (202) within said predetermined rim, electrically connected to said DC amplifier and configured to sense the amount of magnetic flux across said gap. It may further include a magnetic flux sensor. The DC amplifier determines the current in the DC bias winding based on the first signal (114), the second signal (206) from the flux sensor, and the third signal (306) from the power filter. can be configured to determine the amount.

In a second embodiment, a method includes receiving, at a DC amplifier, a first signal associated with a source input current, voltage, power or harmonic level. The method also includes determining the amount of current in the DC bias winding based on the first signal. The method further includes directing the determined amount of current to the DC bias winding by the DC amplifier to improve power regulation, current inrush or harmonic levels. A DC bias winding is electrically connected to the DC amplifier. The magnetic core has multiple limbs and the DC bias winding is wound on one given limb.

Other technical features will be readily apparent to one skilled in the art from the following figures, descriptions and claims.

For a more complete understanding of the present disclosure, reference is made to the following description in conjunction with the accompanying drawings.

1 illustrates an example of an actively controlled power transformer according to the present disclosure; 4 illustrates another example of an actively controlled power transformer according to the present disclosure; 4 illustrates yet another example of an actively controlled power transformer according to the present disclosure; 1 illustrates an example of a signal processing system for use in an actively controlled power transformer according to the present disclosure; 4 illustrates yet another example of an actively controlled power transformer according to the present disclosure; 1 shows a schematic of an example three-stage power filter for use in an actively controlled power transformer according to the present disclosure; Fig. 2 shows a chart showing experimental results for a two-phase power transformer according to the present disclosure; 1 illustrates an example of a power system that can use actively controlled power transformers in accordance with the present disclosure; 1 illustrates an example method for controlling a power transformer according to the present disclosure;

1-9 described below and the various embodiments used to explain the principles of this invention in this patent document are for illustrative purposes only and are not to be construed as limiting the scope of the invention. You shouldn't do anything. Those skilled in the art will appreciate that the principles of the present invention may be implemented in any kind of suitably arranged device or system.

For simplicity and clarity, some features and components are not explicitly shown in all drawings, including those shown in connection with other drawings. It will be appreciated that all features shown in the drawings may be employed in any of the described embodiments. The omission of a feature or component from a particular drawing is for the sake of simplicity and clarity and does not imply that the feature or component cannot be employed in the embodiments described in connection with that drawing. do not have.

As previously mentioned, radar power systems and other power systems often use heavy external electrical equipment to limit current inrush and harmonic filtering to the main power transformer. One example system uses a separate subsystem to limit the inrush current to the main radar transformer, requires over 300 cubic feet of space, and weighs about 1 ton. Therefore, any options for reducing weight or size are welcome. Some current limiting systems utilize a three-phase resistor bank resulting in over 100 kW for a 2 MW radar. These systems can include passive harmonic filters designed for high voltage side inputs. However, these systems do not use current feedback to actively control inrush or peak current. In addition, these filter systems use fixed L-C networks that are load independent, which means that the input line power factor is often overcompensated.

To address these and other issues, the present disclosure provides an actively-controlled power transformer and method of controlling the power transformer. The disclosed transformer features integral and adjustable current limit functions built into the magnetics of the transformer and also allows active tuning of L-C passive filters magnetically coupled to the transformer. As a result, the weight, size and cost of large-scale installations of mobile and ground-based radar power systems and other power systems are greatly reduced.

FIG. 1 shows an example of an actively-controlled power transformer 100 according to this disclosure. As described below, transformer 100 is an actively controlled power transformer that includes integral inrush current limiting and integral harmonic filtering. Although transformer 100 is described as a two-phase autotransformer, the principles described herein can be applied to units with two or more phases, such as single-phase units or three-phase galvanically (electrically) isolated units. can.

As shown in FIG. 1, transformer 100 includes magnetic core 102 having multiple limbs including outer limbs 104-105 and center limb 106. As shown in FIG. Outer limbs 104-105 each include main windings 108-109, each associated with a line input and a line output for powering a load (such as a radar system). For example, the output of transformer 100 can feed an array of alternating current/direct current (AC/DC) power supplies that provide radar pulses. In some embodiments, the input voltage to transformer 100 is approximately 4160 volts and transformer 100 steps down the voltage to an output of approximately 480 volts. Of course, other input and output voltages are possible and within the scope of this disclosure.

Transformer 100 is a two-phase autotransformer with central magnetic flux 116-117 flowing from outer limbs 104-105 to central limb 106. A DC (direct current) bias winding 110 is wrapped around the central rim 106 . Although only one DC (direct current) bias winding 110 is shown in FIG. 1, additional DC bias windings can be included in additional limbs in other embodiments. The flux 116-117 has its saturation level controlled by the DC magnetization level of the DC bias winding 110. FIG.

DC bias winding 110 is electrically connected to DC amplifier 112 . DC amplifier 112 controls the DC current through DC bias winding 110 to control the flux level in transformer 100 . In some embodiments, DC amplifier 112 may provide current to DC bias winding 110 in direct response to a feedback signal 114 generated based on the output current of a radar or other load. DC amplifier 112 includes any suitable structure configured to receive one or more signals and provide a bias current, such as one or more processors, memories, control circuits, and the like. In some cases, feedback signal 114 may be generated by a signal processing system that takes a pulsed radar output current waveform or other waveform, modifies that waveform, and integrates it into feedback signal 114 . Feedback signal 114 may also be based on the voltage waveform of the load output rather than the current waveform. Details of an example signal processing system are provided below.

In operation, DC amplifier 112 receives and samples feedback signal 114 for phase (such as power factor) and amplitude information. Based on analysis of feedback signal 114, DC amplifier 112 determines the amount of current to excite DC bias winding 110 to control saturation of transformer 100, which is directly related to the transformer load. For example, when the load is light (indicated by a higher than normal magnetic flux through core 102), the DC saturation control current can be increased. DC amplifier 112 then sends a determined amount of current to DC bias winding 110 .

The DC amplifier 112 can detect load changes quickly (eg, within 5-10 milliseconds) and actively control the current in the DC bias winding 110 in response to the load changes. This is in contrast to conventional transformers that include a bias winding, but the winding is set at a fixed value and not dynamically controlled. In some embodiments, DC amplifier 112 may only respond to feedback signal 114 derived from the magnitude and phase angle of the load output current. In other embodiments, the feedback signal 114 to the DC amplifier 112 can be more sophisticated and additionally responsive to harmonics of the load output current. Such embodiments are described in more detail below.

Although FIG. 1 shows an example of an actively controlled power transformer 100, various modifications can be made to FIG. For example, the various parts of Figure 1 may be combined, further subdivided, duplicated, omitted, placed in any other suitable arrangement, or additional parts may be added according to particular needs. can be done. In general, power transformers come in a wide variety of configurations, and FIG. 1 is not intended to limit the present disclosure to any particular configuration of power transformers. Also, although FIG. 1 illustrates one example of an operational environment in which an actively controlled power transformer can be used, this functionality can be used in other suitable systems.

FIG. 2 illustrates another example actively controlled power transformer 200 according to this disclosure. As described below, transformer 200 is an actively controlled polyphase power transformer that includes integral inrush current limiting and integral harmonic filtering. Although transformer 200 is described as a two-phase autotransformer, the principles described herein apply to units with two or more phases, such as single-phase units or three-phase galvanic isolation units. be able to.

As shown in FIG. 2, transformer 200 includes various components that are the same as or similar to corresponding components in transformer 100 of FIG. For example, transformer 200 includes a magnetic core 102 with outer limbs 104-105 and a central limb 106. As shown in FIG. Outer limbs 104-105 include main windings 108-109, respectively, and central limb 106 includes a DC bias winding 110. FIG. DC bias winding 110 is electrically connected to DC amplifier 112 .

In transformer 200 , central rim 106 includes magnetic gap 202 , which is the physically air gap region of central rim 106 . A magnetic gap 202 is provided to help control the flux saturation of the transformer 200 . In some embodiments, the magnetic gap 202 may be approximately 3mm-5mm thick, although the magnetic gap 202 may be smaller or larger.

Transformer 200 also includes magnetic flux sensor 204 positioned in or near magnetic gap 202 . Magnetic flux sensor 204 is configured to sense magnetic flux across magnetic gap 202 . The flux sensor 204 can also be electrically connected to the DC amplifier 112 to provide the DC amplifier 112 with information regarding the magnitude and phase of the magnetic flux through the magnetic gap 202 . In operation, flux sensor 204 (continuously, periodically, or at other appropriate times) detects and measures magnetic flux through magnetic gap 202 and provides feedback signal 206 indicative of the magnetic flux to DC amplifier 112 . This is useful as the magnetic flux is highly dependent on the overall magnetic state and can change quickly. Magnetic flux sensor 204 represents any suitable sensing device configured to measure magnetic flux and generate a feedback signal. In some embodiments, the magnetic flux sensor 204 can be a Hall effect probe or a magnetic sensor with a wound magnetic field coil.

In transformer 200, DC amplifier 112 receives both feedback signal 206 from flux sensor 204 and feedback signal 114 from the load output current. DC amplifier 112 processes both signals 206 and 114 using a suitable routine or algorithm to determine the current to apply to DC bias winding 110 to control saturation of transformer 200 . Feedback signal 206 helps modulate the current into DC bias winding 110 to avoid overdriving DC bias winding 110 . This allows fast control of the current limit at any input voltage level. In some embodiments, feedback signal 114 is considered the primary signal and feedback signal 206 is secondary so that DC amplifier 112 gives more weight to feedback signal 114 in determining the current to DC bias winding 110 . Considered as the next signal. Feedback signal 114 typically contains the maximum level of undesired harmonics due to output rectification, and feedback signal 206 typically contains lower levels of harmonics, although this level exceeds acceptable industry standards for line harmonics. there may be. As a result, by comparing the signals 114 and 206, the DC amplifier 112 determines that the transformer essentially rejects the higher harmonics such as the 5th, 7th, 11th, 13th, 19th, 21st harmonics. The amount of attenuation to provide can be determined. However, in other embodiments, feedback signal 206 may be given more priority, or signals 114 and 206 may be given equal priority.

For multi-phase transformers with multiple outputs, the system can include one feedback output current signal from each phase, and the control system uses the summation of the output current signals to determine the optimum DC bias current. junctions). In one embodiment, the transformer 200 comprises multiple limbs, each with its own magnetic core gap, and multiple bias coils, typically arranged as one bias coil per phase.

Although FIG. 2 shows another example of an actively controlled power transformer 200, various modifications can be made to FIG. For example, the various parts of Figure 2 may be combined, further subdivided, duplicated, omitted, or arranged in any other suitable arrangement, or additional parts may be added according to particular needs. can be done. Again, there are various configurations of power transformers, and FIG. 2 is not intended to limit the present disclosure to any particular configuration of power transformers. Also, although FIG. 2 illustrates another example of an operating environment in which actively controlled power transformers can be used, this functionality can be used in other suitable systems.

FIG. 3 illustrates yet another example of an actively controlled power transformer 300 according to this disclosure. As described below, transformer 300 is an actively controlled power transformer that includes integral inrush current limiting and integral harmonic filtering. Although transformer 300 is described as a two-phase autotransformer, the principles described herein can be applied to units with two or more phases, such as single-phase units or three-phase galvanically isolated units.

As shown in FIG. 3, transformer 300 includes various components that are the same as or similar to corresponding components of transformer 100 of FIG. 1 or transformer 200 of FIG. For example, transformer 300 includes a magnetic core 102 with outer limbs 104-105 and a central limb 106. As shown in FIG. Outer limbs 104-105 include main windings 108-109, respectively, and central limb 106 includes a DC bias winding 110. FIG. DC bias winding 110 is electrically connected to DC amplifier 112 . Central rim 106 includes a magnetic gap 202 and magnetic flux sensor 204 is positioned within or near magnetic gap 202 .

Transformer 300 also includes a power filter winding 302 electrically connected to a power filter 304 external to transformer 300 . A power filter winding 302 is wound on the magnetic core 102 and is electrically isolated from the main windings 108-109. As shown in FIG. 3, power filter windings 302 are wound on a portion of magnetic core 102 between central rim 106 and outer rim 105 . In other embodiments, the power filter winding 302 may be wound around the central rim 106, such as from the DC bias winding 110 across the magnetic gap 202, or other suitable location on the magnetic core 102.

Power filter 304 can represent a broad spectrum harmonic filter that can allow harmonic filter levels to be independent of input or output voltage level. In some embodiments, power filter 304 is a passive LC polyphase network power harmonic filter. The L and C components can be connected in either series or parallel resonant circuits. Power filter 304 provides efficient filtering of the main harmonics of the load power. For example, in a six-pulse rectified output power system, power filter 304 filters on the 5th, 7th, 11th, 13th, 19th, and 21st harmonics. be able to. In other systems, eg, 12-pulse or 24-pulse power systems, power filter 304 may provide filtering for other or additional harmonics. The power filter 304 operates without having to draw extra output load current and reduces problematic transformer I ² R heating.

Because the power filter 304 can be electrically isolated from the input and output of the primary load, it can have optimized voltage levels for the power filter 304 . Its voltage is load or power supply independent. The power filter 304 here is directly coupled to the magnetic core 102 of the transformer 300 via the power filter winding 302 . Transformer 300 actively controls the amount of VAR injected into the AC mains by reducing the “leading power factor” (VAR) output of power filter 304 . This limits overcompensation without requiring high power electronic switching. This is in contrast to typical high power filters which tend to overcompensate the AC input line with the leading VAR when the load is light. Such overcompensation can cause the primary system voltage to rise above normal levels.

Power filter 304 can be tuned to one or more dominant harmonics by the configuration of power filter winding 302 . In some embodiments, the power filter winding 302 may include multiple independent windings, each tuned to a different harmonic. In some embodiments, the 11th, 13th and 19th harmonics may cause the most significant problems. Thus, the power filter winding 302 can include three independent shunt-connected windings each tuned to their harmonics, an example of which is shown in Table 1. In some embodiments, the total reactive power of the filter is approximately 230 kVAR for a 2500 kVA mains input. Of course, other embodiments are possible, including those with other total filter reactive power amounts and with more, less, or different numbers of harmonics.

パワーフィルタ304を異なる高調波に同調させるようにパワーフィルタ巻線302を構成することにより、１つ以上の高価な専用フィルタ（11 kV、13.8 kV、4160Vフィルタなど）を持つのではなく、パワーフィルタ304に安価な市販（COTS）フィルタ（480V高調波フィルタなど）を使用することが可能である。これにより、パワーシステムの全体的なサイズ、重量、及びコストが削減される。

By configuring the power filter windings 302 to tune the power filter 304 to different harmonics, the power filter can be tuned as opposed to having one or more expensive dedicated filters (11 kV, 13.8 kV, 4160V filters, etc.). It is possible to use an inexpensive off-the-shelf (COTS) filter (such as a 480V harmonic filter) for the 304. This reduces the overall size, weight and cost of the power system.

Power filter 304 can provide feedback signal 306 to DC amplifier 112 so that transformer 300 provides an actively controlled version of power filter 304 . A feedback signal 306 can indicate the harmonic level sensed at the power filter 304 . In transformer 300 there is feedback signal 306 in addition to feedback signal 114 from load output current or load voltage and feedback signal 206 from flux sensor 204 . These signals 114, 206, 306 are input to the DC amplifier 112, which processes the signals 114, 206, 306 using suitable routines or algorithms to determine the current to the DC bias winding 110 and control the flux level. can. In some embodiments, there is a hierarchy to signals 114, 206, 306, each signal having an electrical integrator circuit associated with each input. For example, signal 114 may be the dominant feedback signal and have the shortest internal time delay (lag), signal 206 may have second priority and medium integrator time delay, and signal 306 can have the last priority and longest integrator time delay in the signal processing scheme.

In operation, the DC amplifier 112 monitors the feedback signal 114 from the load output current for phase (such as power factor) and amplitude and adjusts the excitation level of the DC bias winding 110 . When the load is light, as indicated by the higher than normal magnetic flux through core 102, DC amplifier 112 increases the saturation control current to DC bias winding 110, for example within 5-10 milliseconds for a 60 Hz system. If the system is at a higher frequency such as 400Hz, the response time is based on quarter cycle response time. This increase in DC control current reduces the induced voltage in the power filter circuit and reduces the resonance current in power filter 304 . The DC saturation level also changes the inductance of the power filter 304 . As the control current to the DC bias winding 110 increases, the AC inductance of each filter stage decreases, keeping the capacitance constant and thus de-tuning the passive power filter 304 .

Although FIG. 3 shows yet another example of an actively controlled power transformer 300, various modifications can be made to FIG. For example, the various parts of Figure 3 may be combined, further subdivided, duplicated, omitted, or arranged in any other suitable arrangement, or additional parts may be added according to particular needs. can be done. Again, there are various configurations of power transformers, and FIG. 3 is not intended to limit the present disclosure to any particular configuration of power transformers. Also, although FIG. 3 illustrates another example of an operating environment in which actively controlled power transformers can be used, this functionality can be used in other suitable systems.

FIG. 4 shows an example signal processing system 400 for use in an actively controlled power transformer according to this disclosure. For ease of explanation, system 400 is described as being used with transformer 300 of FIG. However, at least portions of system 400 may be used with other suitable devices or systems, including transformer 100 of FIG. 1 and transformer 200 of FIG.

As shown in FIG. 4, system 400 includes load current pulse sensing device 402 , rectifier and filter 404 , and integrator 406 . A load current pulse sensing device 402 senses a pulsed load and a high rate of rise (di/dt) output current 410 (such as from a radar subarray power supply) and outputs a waveform that is input to a rectifier and filter 404. Generate a signal. A rectifier and filter 404 rectifies the waveform signal and low pass filters the signal. It is then integrated into feedback signal 114 by integrator 406 and output to DC amplifier 112 . Also shown in FIG. 4 are the feedback signal 206 from the flux sensor 204 to the DC amplifier 112 and the feedback signal 306 from the power filter 304 to the DC amplifier 112 . DC amplifier 112 has at its input the summation junction of these three feedback signals 114, 206, 306, each signal having a distinct lag-lead network and a distinct time constant. It is a further purpose of the system 400 to prevent high di/dt or high surge load currents from appearing on the transformer primary winding and to buffer mains power from high peak loads.

Although FIG. 4 shows an example signal processing system 400 for use in an actively controlled radar power transformer, various modifications can be made to FIG. For example, the various parts of FIG. 4 may be combined, further subdivided, duplicated, omitted, placed in any other suitable arrangement, or additional parts added according to particular needs. can be done. As a specific example, load output current 410 may instead be load output voltage. In such embodiments, the load current pulse sensing device 402 can be replaced with a load voltage sensing device. A further purpose of the voltage sensing device is to prevent high dv/dt load surges from appearing on the transformer input winding. In general, there are many different configurations of signal processing systems, and FIG. 4 is not intended to limit the present disclosure to any particular configuration of signal processing systems. Also, although FIG. 4 illustrates one example of an operational environment in which the signal processing system may be used, the functionality may be used in other suitable systems.

FIG. 5 illustrates yet another example actively controlled power transformer 500 according to this disclosure. As described below, transformer 500 is an actively controlled power transformer that includes integral inrush current limiting and integral harmonic filtering. Although transformer 500 is described as a two-phase autotransformer, the principles described herein can be applied to units with two or more phases, such as single-phase units or three-phase galvanically (electrically) isolated units. can.

As shown in FIG. 5, transformer 500 is very similar to transformer 300 of FIG. However, in addition to one power filter 304 coupled to power filter winding 302 , transformer 500 includes additional power filters 504 coupled to additional power windings 502 . A power filter winding 502 is wrapped around the magnetic core 102 and is electrically isolated from the main windings 108-109. As shown in FIG. 5, a power filter winding 502 is wrapped around a portion of magnetic core 102 between central rim 106 and outer rim 104 . In other embodiments, the power filter winding 502 may be wound around the central rim 106 such as from the DC bias winding 110 across the magnetic gap 202 or other suitable location of the magnetic core 102 .

Similar to power filter 304, power filter 504 can represent a broad spectrum harmonic filter that can allow harmonic filter levels to be independent of input or output voltage level. In some embodiments, power filter 504 is a passive L-C polyphase network power harmonic filter. The L and C components can be connected in either series or parallel resonant circuits. Power filter 504 , like power filter 304 , may also provide feedback signal 306 to DC amplifier 112 .

Although FIG. 5 shows yet another example of an actively controlled power transformer 500, various modifications can be made to FIG. For example, the various components of FIG. 5 may be combined, further subdivided, duplicated, omitted, placed in any other suitable arrangement, or additional components added according to particular needs. can be done. FIG. 5 is not intended to limit the present disclosure to any particular configuration of power transformers. Also, FIG. 5 illustrates another example of an operating environment in which actively controlled power transformers can be used, although this functionality can be used in other suitable systems.

FIG. 6 shows a schematic diagram of an example three-stage power filter 600 for use in an actively controlled power transformer according to this disclosure. For ease of explanation, filter 600 may represent power filter 304 of FIG. 3 or power filter 504 of FIG. However, power supply filter 600 may be used with any other suitable device or system, including transformer 100 of FIG. 1 and transformer 200 of FIG.

As shown in FIG. 6, the power supply filter 600 can be a 230 kVAR power supply filter as listed in Table 1, thereby providing L-C components including L components 601-603 and C components 604-606. Selective tuning of filter 600 to the 11th, 13th and 19th harmonics is achieved by the three branches of . In some embodiments, each branch has a separate current sensor that provides feedback to the master controller through a summing junction to form feedback signal 306 . Power filter 600 is coupled to power filter winding 610 , which may be a single-phase concentric winding disposed on one or more limbs of a transformer such as transformer 300 .

Although FIG. 6 shows an example power filter 600 for use in an actively controlled power transformer, various modifications can be made to FIG. For example, the various parts of Figure 6 may be combined, further subdivided, duplicated, omitted, placed in any other suitable arrangement, or additional parts may be added according to particular needs. can be done. Also, although the power filter 600 is described as being tuned for the 11th, 13th and 19th harmonics, the power filter 600 can be tuned for other harmonics.

FIG. 7 is a graph showing experimental results for a two-phase 4160 volt 400 Hz power transformer rated at 1000 kVA with a DC bias winding mounted on the center limb with a bias current of 0-100 amps, similar to transformer 100 of FIG. It shows 700. In graph 700, trace 701 shows the AC input current and trace 702 shows the self-impedance of the AC winding. When the bias current is 0, the AC winding self-impedance is a maximum of 6961 ohms, and when the bias current is 100 amps, the AC winding self-impedance is reduced to 250 ohms, with a 28:1 ratio by changing the bias. showing variation. Clearly the transformer is operating in and out of the normal saturation region. Experimental results showed nonlinear changes in impedance or inductance over a wide range of bias currents, which were continuous DC magnetization changes rather than pulsed magnetization.

FIG. 8 illustrates an example power system 800 that can use actively controlled power transformers in accordance with this disclosure. In some embodiments, power system 800 (or similar system) can be used with one or more transformers described herein.

As shown in FIG. 8, power system 800 includes phase shift transformer 802 that receives three-phase AC power from AC power source 804 . In some embodiments, power system 800 is a 48-pulse system with harmonic current filtering in transformer 802 . In some embodiments, phase shift transformer 802 may represent (or be) transformer 100, transformer 200, transformer 300, or transformer 500. Transformer 802 converts the received AC power and outputs six-phase power to multiple loads 806-809. Saturation in transformer 802 is controlled by a DC bias controller 812 similar to DC amplifier 112 .

Although FIG. 8 illustrates an example power system 800, various modifications can be made to FIG. For example, the various parts of Figure 8 may be combined, further subdivided, duplicated, omitted, or arranged in any other suitable arrangement, or additional parts may be added according to particular needs. can be done.

FIG. 9 illustrates an example method 900 of controlling a power transformer according to this disclosure. For ease of explanation, method 900 of FIG. 9 may be described as being performed using transformer 100 of FIG. 1, transformer 200 of FIG. 2, or transformer 300 of FIG. However, method 900 may involve the use of other suitable devices or systems.

As shown in FIG. 9, at step 902, a DC amplifier of a transformer receives a first signal related to load output current or voltage. This includes, for example, DC amplifier 112 that receives feedback signal 114 . A DC amplifier 112 is electrically connected to a DC bias winding 110 wrapped around a particular limb 106 of the magnetic core 102 of the transformer 100,200,300. The magnetic core 102 has multiple rims 104-106 including a particular rim 106. As shown in FIG.

At step 904, the DC amplifier can optionally receive a second signal from a magnetic flux sensor electrically connected to the DC amplifier. This includes, for example, DC amplifier 112 that receives feedback signal 206 from flux sensor 204 . A second signal may be generated by the flux sensor 204 in response to measuring the amount of magnetic flux passing through the gap 202 of the given rim 106 .

At step 906, the DC amplifier may optionally receive a third signal from a power filter coupled to a power filter winding wrapped around the magnetic core. This includes, for example, DC amplifier 112 that receives feedback signal 306 from power filter 304 .

At step 908, the DC amplifier determines the amount of current in the DC bias winding based on the first signal and optionally the second and third signals. This includes, for example, DC amplifier 112 determining the amount of current in DC bias winding 110 based on feedback signal 114 , feedback signal 206 and feedback signal 306 .

At step 910, the DC amplifier transmits the determined amount of current through the DC bias winding. This includes, for example, DC amplifier 112 sending current in mark-space pulses or sending a continuous stream through DC bias winding 110 . The current through the DC bias winding 110 is configured to control flux saturation within the magnetic core 102 of the transformer 100, 200, 300 and change the magnetic permeability of the component magnetic rims.

Although FIG. 9 illustrates an example method 900 of controlling a power transformer, various modifications can be made to FIG. For example, although shown as a series of steps, various steps in FIG. 9 may overlap, occur in parallel, occur in different orders, or occur any number of times.

As noted above, the disclosed embodiments provide an actively controlled power transformer capable of current limiting and also active tuning of the L-C filter. This is currently the case in mobile or land-based radar systems requiring large filter banks, large power transformers with large inrush current limiting devices, current limiting and harmonic It is advantageous for many applications such as marine power systems that require filtering. The disclosed embodiments reduce the size and weight of the overall power system (such as about a 20% weight reduction in some systems) and allow the input power to be overcompensated for high leading power factor loads. To avoid. The disclosed embodiments are applicable to both autotransformers and galvanic isolation transformers in low voltage or high voltage designs.

It may be advantageous to provide definitions of certain words and phrases used throughout this patent document. The terms "including" and "having" and derivatives thereof mean inclusion without limitation. The term "or" has the inclusive meaning "and/or." The term "associated with" and its derivatives includes, includes, interconnects, includes, includes, connects, couples, communicates, cooperates, interleaves, juxtaposes, contiguous, It means to be bound, to have, to possess, to have a relationship with, etc. The phrase "at least one," when used with a list of items, means that different combinations of one or more of the items listed can be used, and that only one item in the list may be required. . For example, "at least one of A, B and C" includes any combination of A, B, C, A and B, A and C, B and C, A and B and C.

The description of the present application should not be read to imply that any particular element, step or function is essential or critical to the claims. The claims are defined only by the allowed claims. Furthermore, "means" or "steps" in any claim are not limited to the embodiments in any of the appended claims or claim elements. "mechanism", "module", "device", "unit", "part", "element", "member", "apparatus", "machine", "system", "processor" or "controller" in a claim Use of terms such as "controller" is understood and intended to refer to structures known to those skilled in the relevant art, further modified or enhanced by the features of the claims themselves. , but not limited to the embodiments.

Although this disclosure describes certain embodiments and generally associated methods, modifications and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other modifications, substitutions and alterations are possible without departing from the spirit and scope of this disclosure as defined by the following claims.

Claims (22)

Being a transformer:
a magnetic core having multiple limbs;
a DC bias winding wound around a given one of said limbs; and a DC amplifier electrically connected to said DC bias winding;
receiving a first signal related to load output current or voltage;
a DC amplifier for determining an amount of current in the DC bias winding based on the first signal; and sending the determined amount of current through the DC bias winding;
including transformers. 2. The transformer of claim 1, wherein said determined amount of current is configured to control flux saturation of said magnetic core. 2. The transformer of claim 1, wherein said predetermined rim is the central rim of said magnetic core. 2. The transformer of claim 1, wherein said first signal is generated based on an integral value of said load output current or voltage. a magnetic flux sensor positioned within a gap within said predetermined rim, said magnetic flux sensor electrically connected to said DC amplifier and configured to sense the amount of magnetic flux across said gap;
2. The transformer of claim 1, further comprising: 6. The transformer of claim 5, wherein said DC amplifier is configured to determine the amount of current in said DC bias winding based on said first signal and a second signal from said flux sensor. 7. The transformer of claim 6, wherein the flux sensor is configured to generate the second signal in response to measuring the amount of magnetic flux across the gap within the given rim. a power filter coupled to a power filter winding wound around the magnetic core;
6. The transformer of claim 5, further comprising: The DC amplifier is configured to determine the amount of current in the DC bias winding based on the first signal, a second signal from the flux sensor, and a third signal from the power filter. 9. The transformer of claim 8, wherein 9. The transformer of claim 8, wherein said power filter is electrically isolated from primary load inputs and outputs. 9. The transformer of claim 8, wherein said power filter comprises a polyphase power harmonic filter. 9. The transformer of claim 8, wherein the power filter winding comprises multiple windings, each tuned to a different harmonic. receiving, with a DC amplifier, a first signal related to the load output current or voltage;
determining an amount of current in a DC bias winding based on said first signal; and sending said determined amount of current through said DC bias winding by said DC amplifier;
including
the DC bias winding is electrically connected to the DC amplifier; and the magnetic core has a plurality of limbs, the DC bias winding being wrapped around one predetermined limb;
Method. 14. The method of claim 13, wherein the determined amount of current is configured to control flux saturation of the magnetic core. 14. The method of claim 13, wherein said first signal is generated based on an integral of said load output current or voltage. sensing the amount of magnetic flux passing through a gap in said given rim with a flux sensor, said flux sensor positioned within said gap and electrically connected to said DC amplifier;
14. The method of claim 13, further comprising: 17. The method of claim 16, wherein determining the amount of current in the DC bias winding is based on the first signal and a second signal from the flux sensor. using a power filter coupled to a power filter winding wrapped around the magnetic core;
17. The method of claim 16, further comprising: 19. The method of claim 18, wherein determining the amount of current in the DC bias winding is based on the first signal, a second signal from the flux sensor, and a third signal from the power filter. 19. The method of claim 18, wherein the power filter windings comprise multiple windings, each tuned to a different harmonic. 19. The method of claim 18, wherein said power filter winding has a voltage level independent of line voltage or load voltage. 19. The method of claim 18, wherein the power filter windings include at least one capacitive element in each phase and at least one inductive filter element in each phase.

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